Leukemia includes a heterogeneous group of neoplasms that infiltrate bone marrow with mature or immature cells of the white blood cell lineage. In leukemia, bone marrow infiltration usually occurs diffusely, with a diffuse decrease in the marrow signal intensity on T1-weighted images. MRI is highly sensitive for detecting bone marrow infiltration, but its specificity is poor, leaving the diagnosis of leukemia to peripheral blood smears and bone marrow biopsy.

T1-weighted imaging is the most sensitive pulse sequence to assess abnormal bone marrow signal intensity.